docs: def run(self):
          """ Run an infinite REQ/REP loop. """
          while True:
              req = self.socket.recv_json()
  
              try:
                  answer = self.handle_request(req)
                  self.socket.send(json.dumps(answer))
  
              except (AttributeError, TypeError) as e:
                  self.socket.send_json({'error': str(e)})